What is it with London and postcodes? No other country or city places such an importance on them and if you are going to be living in London you’ll have to learn how to understand them and use them. If you are looking for a London rental and are browsing through adverts and estate agent listings, oftentimes the location of the London apartment will just be indicated by the postcode, so learning how to identify postcodes will help you immensely in your day to day life in London.